Anisotropic conductive film, composition for the same, and apparatus including the same

ABSTRACT

An anisotropic conductive film includes a binder part, a curing part, an initiator, and conductive particles, wherein the binder part includes at least one of a nitrile butadiene rubber (NBR) resin and a urethane resin, wherein the anisotropic conductive film has an electrical conductivity of more than 0 μS/cm to about 100 μS/cm.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation application based on pending application Ser. No.13/241,811, filed Sep. 23, 2011 (now U.S. Pat. No. 8,608,985), theentire contents of which is hereby incorporated by reference.

BACKGROUND

1. Field

Embodiments relate to an anisotropic conductive film, an anisotropicconductive film composition for the same and an apparatus including thesame.

2. Description of the Related Art

An anisotropic conductive film is an adhesive film in which conductiveparticles, such as, for example, metal particles of nickel, gold, etc.,or polymer particles coated with such metals are dispersed. When theanisotropic conductive film is disposed between circuits to be connectedand is subjected to heat and pressure under predetermined conditions,circuit terminals are electrically connected by the conductiveparticles. A pitch between adjacent circuits may be filled with aninsulating adhesive resin, such that the conductive particles do notcontact one another, providing strong insulating properties.

SUMMARY

According to an embodiment, there is provided an anisotropic conductivefilm including a binder part, a curing part, an initiator, andconductive particles, wherein the binder part includes at least one of anitrile butadiene rubber (NBR) resin and a urethane resin, theanisotropic conductive film has an electrical conductivity of more than0 μS/cm to about 100 μS/cm.

The anisotropic conductive film may have an ion content of more than 0ppm to about 100 ppm.

The anisotropic conductive film may have an ion content of more than 0ppm to about 50 ppm.

The binder part may include the NBR resin, and the NBR resin may have anion content of more than 0 ppm to about 100 ppm.

The binder part may include the urethane resin, and the urethane resinmay have an ion content of more than 0 ppm to about 100 ppm.

The binder part may further include an acrylic resin.

The binder part may include about 20 to about 80% by weight (wt %) ofthe acrylic resin and about 20 to about 80 wt % of the NBR resin, theNBR resin having an ion content of more than 0 ppm to about 100 ppm.

The binder part may include about 20 to about 80 wt % of the acrylicresin and about 20 to about 80 wt % of the urethane resin, the urethaneresin having an ion content of more than 0 ppm to about 100 ppm.

The binder part may include about 20 to about 90 wt % of the acrylicresin, about 5 to about 55 wt % of the NBR resin, the NBR resin havingan ion content of more than 0 ppm to about 100 ppm and about 5 to about40 wt % of the urethane resin, the urethane resin having an ion contentof more than 0 ppm to about 100 ppm.

The binder part may further include at least one thermoplastic resinselected from acrylonitrile, polyamide, olefin and silicone resins.

The curing part may include at least one of a urethane (meth)acrylateand a (meth)acrylate monomer.

The initiator may include a radical initiator.

The anisotropic conductive film may include about 20 to about 78 wt % ofthe binder part, about 20 to about 50 wt % of the curing part, about 1to about 10 wt % of the radical initiator and about 1 to about 20 wt %of the conductive particles in a solid state.

The anisotropic conductive film may further include a polyurethane bead.

The polyurethane bead may include an ion-exchanged polyurethane bead.

The polyurethane bead may have an ion content of more than 0 ppm toabout 10 ppm.

The polyurethane bead may be included in an amount of about 1 to about10 parts by weight based on 100 parts by weight of the anisotropicconductive film in terms of solid content.

According to an embodiment, there is provided a composition for ananisotropic conductive film, the composition including a binder part, acuring part, an initiator, and conductive particles. The binder part mayinclude at least one of a nitrile butadiene rubber (NBR) resin and aurethane resin. The composition may have an ion content of more than 0about 100 ppm.

According to an embodiment, there is provided a anisotropic conductivefilm that is a product of the composition for an anisotropic conductivefilm. The anisotropic conductive film may have an electricalconductivity of more than 0 μS/cm to about 100 μS/cm.

According to an embodiment, there is provided an apparatus including theanisotropic conductive film.

DETAILED DESCRIPTION

Korean Patent Application No. 10-2010-0138221, filed on Dec. 29, 2010,in the Korean Intellectual Property Office, and entitled: “AnisotropicConductive Film, Composition for the Same, and Apparatus Including theSame,” is incorporated by reference herein in its entirety.

Example embodiments will now be described more fully hereinafter;however, embodiments may be embodied in different forms and should notbe construed as limited to the example embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the inventionto those skilled in the art.

In one embodiment, an anisotropic conductive film includes a binderpart, a curing part, an initiator, and conductive particles and has anion content of more than 0 ppm to about 100 ppm. Specifically, the ioncontent may be more than about 0 and less than about 50 ppm. In thiscase, a corrosion possibility in a metal electrode decreases, therebyimproving reliability.

The ion content of the anisotropic conductive film may be measured byion chromatography using an automated combustion system.

The anisotropic conductive film may be manufactured using a plurality ofcomponents including a binder part, conductive particles, and the like.Thus, a conventional method of measuring the ion content of eachcomponent and the ion content of the entire film may not be effective todetermine whether corrosion occurs under the application of voltage andcurrent when the film is actually connected to a circuit. Therefore, theelectrical conductivity of the anisotropic conductive film may bemeasured in advance to identify whether the conductivity is more than 0μS/cm to about 100 μS/cm, thereby determining in advance whethercorrosion will occur between components when the anisotropic conductivefilm is connected to the circuit. The electrical conductivity may bemeasured by any suitable method. For example, about 0.4 g of an adhesivefilm may be put into about 20 g of deionized water (DIW) and boiled atabout 100° C. for about 10 hours, after which the electricalconductivity of ions dissolved in the water may be measured using aconductivity meter. Other methods may be used. Specifically, theelectrical conductivity may be in a range from more than 0 μS/cm toabout 30 μS/cm.

Binder Part

The binder part may function as a matrix of the anisotropic conductivefilm and may include at least one of a nitrile butadiene rubber (NBR)resin and a urethane resin.

The binder part may be present in the anisotropic conductive film in anamount of about 20 to about 78 wt % in terms of solid content. Withinthis range, excellent film formability may be obtained and electricalconductivity may not become high. Specifically, the amount of the binderpart may be about 30 to about 75 wt %.

Herein, the term “ion” refers to ions produced in a process ofmanufacturing a copolymer resin or a bead through polymerization ofmonomers or the like. For example, the term “ion” may include Na⁺ andCl⁻ ions, without being limited thereto.

The ion content may be measured by any suitable method, such as, forexample, ion chromatography using an automated combustion system.

The NBR resin may have an ion content of more than 0 ppm to about 100ppm. Within this range, the anisotropic conductive film may have lowelectrical conductivity and may not cause corrosion when connected to acircuit. Specifically, the ion content may be more than about 0 and lessthan about 20 ppm.

The NBR resin having an ion content of more than 0 ppm to about 100 ppmmay be produced by ion exchange treatment of an NBR resin. For example,the NBR resin may be produced by a dilution process in which an NBRresin is diluted with a solvent having a low solubility for the NBRresin but favorably dissolving ions or the like, to eliminate ionimpurities, without being limited thereto. For example, the solvent maybe MeOH. Through ion exchange treatment, the ion content of the NBRresin may be reduced.

The NBR resin may be a copolymer produced by emulsion polymerization ofacrylonitrile and butadiene. The content of acrylonitrile and thecontent of butadiene may be appropriately selected. The polymerizationmethod may be appropriately selected.

The NBR resin may have a weight average molecular weight of about 50,000to about 2,000,000 g/mol.

The urethane resin may have an ion content of more than 0 ppm to about100 ppm. Within this range, the anisotropic conductive film may have alow electrical conductivity and may not cause corrosion when connectedto a circuit. Specifically, the ion content may be more than about 0 andless than about 10 ppm.

The urethane resin having an ion content of more than 0 ppm to about 100ppm may be produced by ion exchange treatment of a urethane resin. Forexample, the urethane resin may be produced by a dilution process usingmethyl ethyl ketone in the same manner as the NBR resin, without beinglimited thereto. Through ion exchange treatment, the ion content of theurethane resin may be reduced.

The urethane resin may be a polymer resin having a urethane bond andproduced by polymerization of isophorone diisocyanate andpolytetramethylene glycol, without being limited thereto.

The urethane resin may have a weight average molecular weight of about50,000 to about 2,000,000 g/mol.

The binder part may further include an acrylic resin.

The acrylic resin may have a glass transition temperature of about 30 toabout 120° C. and may have an acid value of about 0-150 mgKOH/mg.

The acrylic resin may have a weight average molecular weight of about50,000 to about 2,000,000 g/mol. Within this range, appropriate tackproperties may be obtained, enabling proper formation of a film,excellent compatibility with components included in the curing part maybe secured and phase separation may not occur.

The acrylic resin may be produced by polymerization of a (meth)acrylicmonomer and/or a monomer polymerizable therewith. For example, theacrylic resin may be prepared by polymerization of at least one monomerselected from (meth)acrylate, (meth)acrylic acid, vinyl acetate, andacrylic monomers or modifications thereof which have a C2 to C10 alkylgroup. The polymerization may be conducted by any suitable method.

The acrylic resin may be present in the binder part in an amount ofabout 20 to about 90 wt %, preferably about 20 to about 80 wt % in termsof solid content. Within this range, proper film formability can besecured.

In one embodiment, the binder part may include the acrylic resin and theNBR resin having an ion content of more than 0 ppm to about 100 ppm. Inthis case, the binder part may include about 20 to about 80 wt % of theacrylic resin and about 20 to about 80 wt % of the NBR resin having anion content of more than 0 ppm to about 100 ppm in terms of solidcontent. Within this range, excellent film formability may be obtained,and electrical conductivity may not be high, so that corrosion may notoccur when connected to a circuit. Specifically, the binder part mayinclude about 30 to about 70 wt % of the acrylic resin and about 30 toabout 70 wt % of the NBR resin having an ion content of more than 0 ppmto about 100 ppm in terms of solid content.

The binder part may further include a urethane resin that is notsubjected to ion exchange treatment, or a urethane resin having an ioncontent greater than about 100 ppm. These resins may be included in acontent of about 1 to about 10 parts by weight based on about 100 partsby weight of the binder part. Within this range, the electricalconductivity of a film may not become high.

In another embodiment, the binder part may include the acrylic resin andthe urethane resin having an ion content of more than 0 ppm to about 100ppm. In this case, the binder part may include about 20 to about 80 wt %of the acrylic resin and about 20 to about 80 wt % of the urethane resinhaving an ion content of more than 0 ppm to about 100 ppm in terms ofsolid content. Within this range, excellent film formability may beobtained, and electrical conductivity may not be high, so that corrosionmay not occur when connected to a circuit. Specifically, the binder partmay include about 30 to about 70 wt % of the acrylic resin and about 30to about 70 wt % of the urethane resin having an ion content of morethan 0 ppm to about 100 ppm in terms of solid content.

The binder part may further include an NBR resin that is not subjectedto an ion exchange treatment or an NBR resin having an ion contentgreater than about 100 ppm. These resins may be included in a content ofabout 1 to about 10 parts by weight based on about 100 parts by weightof the binder part. Within this range, the electrical conductivity of afilm may not become high.

In a further embodiment, the binder part may include the acrylic resin,the NBR resin having an ion content of more than 0 ppm to about 100 ppm,and the urethane resin having an ion content of more than 0 ppm to about100 ppm. In this case, the binder part may include about 20 to about 90wt % of the acrylic resin, about 5 to about 55 wt % of the NBR resinhaving an ion content of more than 0 ppm to about 100 ppm, and about 5to about 40 wt % of the urethane resin having an ion content of morethan 0 ppm to about 100 ppm in terms of solid content. Within thisrange, excellent film formability can be obtained, and electricalconductivity may not be high, so that corrosion may not occur whenconnected to a circuit. Specifically, the binder part may include about20 to about 40 wt % of the acrylic resin, about 30 to about 55 wt % ofthe NBR resin having an ion content of more than 0 ppm to about 100 ppm,and about 30 to about 40 wt % of the urethane resin having an ioncontent of more than 0 ppm to about 100 ppm in terms of solid content.

In the film according to embodiments, the binder part may furtherinclude a thermoplastic resin included in a binder of an anisotropicconductive film. For example, the thermoplastic resin may include atleast one of acrylonitrile, polyamide, olefin, and silicone resins,without being limited thereto.

Curing Part

The anisotropic conductive film according to embodiments may include atleast one of urethane (meth)acrylates and (meth)acrylate monomers.

The curing part may be present in the anisotropic conductive film in anamount of about 20 to about 50 wt % in terms of solid content. Withinthis range, excellent properties in terms of adhesion, appearance, etc.,can be obtained, and reliability and stability can be obtained.Specifically, the amount may be about 23 to about 40 wt %.

The urethane (meth)acrylates include a urethane bond and a double bondat opposite terminals. The urethane (meth)acrylates may be polymericmaterials produced by any suitable polymerization method.

The urethane (meth)acrylate may have a weight average molecular weightof about 500 to about 30,000 g/mol. Within this range, proper filmformability and excellent compatibility may be obtained.

The urethane (meth)acrylate may be present in the anisotropic conductivefilm in an amount of about 10 to about 30 wt %, preferably about 20 toabout 30 wt % in terms of solid content. Within this range, theanisotropic conductive film can have excellent compatibility.

The (meth)acrylate monomers may serve as a diluent. The (meth)acrylatemonomers may include at least one of 1,6-hexanediol mono(meth)acrylate,2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate, 1,4-butanediol (meth)acrylate, 2-hydroxyethyl(meth)acryloyl phosphate, 4-hydroxycyclohexyl (meth)acrylate, neopentylglycol mono(meth)acrylate, trimethylolethane di(meth)acrylate,trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate,dipentaerythritol penta(meth)acrylate, pentaerythritolhexa(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerindi(meth)acrylate, hydrofurfuryl (meth)acrylate, isodecyl (meth)acrylate,2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate, lauryl(meth)acrylate, 2-phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate,tridecyl (meth)acrylate, ethoxylated nonylphenol (meth)acrylate,ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate,tetraethylene glycol di(meth)acrylate, polyethylene glycoldi(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, tripropyleneglycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate,cyclohexanedimethanol di(meth)acrylate, phenoxy t-glycol (meth)acrylate,2-methacryloyloxymethyl phosphate, 2-methacryloyloxyethyl phosphate,dimethyloltricyclodecane di(meth)acrylate, trimethylolpropane benzoateacrylate and mixtures thereof, without being limited thereto.

The (meth)acrylate monomers may be present in the anisotropic conductivefilm in an amount of about 10 to about 20 wt % in terms of solidcontent. Within this range, the anisotropic conductive film may havehigh connection reliability.

The curing part may further include acetals, carbodiimides, or the likein addition to at least one of urethane (meth)acrylates and(meth)acrylate monomers.

Initiators

The anisotropic conductive film may include an initiator, such as, forexample, a radical initiator. The radical initiator may include aphotopolymerization initiator, a heat-curing initiator and a mixturethereof. Specifically, a heat-curing initiator may be used.

The initiator may be present in the anisotropic conductive film in anamount of about 1 to about 10 wt % in terms of solid content. Withinthis range, sufficient reaction for curing may be performed andexcellent properties in terms of adhesion and reliability may beobtained with proper molecular weight after bonding. Specifically, theamount may be about 1 to about 5 wt %.

The heat-curing initiator may include, without being limited to,peroxide and azo initiators. Examples of the peroxide initiator mayinclude, without being limited to, lauryl peroxide, benzoyl peroxide andcumene hydroperoxide. Examples of the azo initiator may include, withoutbeing limited to, 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile),dimethyl-2,2′-azobis(2-methylpropionate) and2,2′-azobis(N-cyclohexyl-2-methyl-propionamide).

Conductive Particles

The anisotropic conductive film includes the conductive particles usedas fillers to impart conductive performance.

The conductive particles may be present in the anisotropic conductivefilm in an amount of about 1 to about 30 wt % in terms of solid content.Within this range, electric conduction may be properly performed, andshort circuits may be prevented. The amount of the conductive particlesmay be properly determined based on uses of the anisotropic conductivefilm and may substantially differ. Specifically, the amount may be about1 to about 20 wt %.

The conductive particles may include at least one of metal particlesincluding gold, silver, nickel, copper or solder metals; carbonparticles; metal-coated resin particles, such as particles ofpolyethylene, polypropylene, polyester, polystyrene, polyvinyl alcohol,or a modified resin thereof, coated with gold, silver, nickel, copper orsolder metals; and insulated conductive particles obtained by coatingthe metal-coated resin particles with insulating particles.

The conductive particles may have a diameter of about 1 to about 20 μM,without being limited thereto, in view of adhesion and connectionreliability.

The anisotropic conductive film may further include polyurethane beads.The polyurethane beads may be spherical organic fine particles of across-linked urethane resin.

The polyurethane beads may be included in the binder part along with theacrylic resin, the NBR resin having an ion content of more than 0 ppm toabout 100 ppm and/or the urethane resin having an ion content of morethan 0 ppm to about 100 ppm.

Polyurethane beads that are subjected to ion exchange treatment may beused. The ion exchange treatment of the polyurethane beads may beconducted by any suitable method, e.g., a dilution process using asolvent or a process using a monomer that does not generate residualions. Through the ion exchange treatment, the ion content of thepolyurethane bead may be decreased and preferably may be more than about0 and less than about 10 ppm. Within this range, the electricalconductivity of the film may not become high, and corrosion may notoccur when connected to a circuit.

The polyurethane beads may have a diameter of about 0.5 to about 10 μmwithout being limited thereto.

The polyurethane beads may be present in an amount of about 1 to about10 parts by weight, or specifically, about 1 to about 5 parts by weight,based on about 100 parts by weight of the anisotropic conductive film interms of solid content. Within this range, the electrical conductivityof the film may not become high and corrosion may not occur whenconnected to a circuit.

Further, the anisotropic conductive film may further include additives,e.g., a polymerization inhibitor, an antioxidant, a heat stabilizer,etc., in order to provide additional properties without hinderingfundamental properties. The additives may be present in the anisotropicconductive film in an amount of about 0.01 to about 10 wt % in terms ofsolid content, without being limited thereto.

The polymerization inhibitor may be selected from hydroquinone,hydroquinone monomethyl ether, p-benzoquinone, phenothiazine andmixtures thereof. The antioxidant may include phenolic orhydroxycinnamate compounds, e.g.,tetrakis[methylene(3,5-di-tert-butyl-4-hydroxycinnamate)]methane and3,5-bis-(1,1-dimethylethyl)-4-hydroxybenzenepropanethiol-di-2,1-ethanediyl ester.

The anisotropic conductive film may be formed of an anisotropicconductive film composition described as follows. The anisotropicconductive film may be manufactured using a suitable device orequipment. For example, the anisotropic conductive film composition maybe dissolved in an organic solvent including toluene or the like andliquefied, and then may be stirred for predetermined time at a raterange in which the conductive particles are not ground. The product maybe applied onto a release film to a thickness of about 10 to about 50 μmand dried over a predetermined time to volatilize the organic solvent ormay be additionally cured using ultraviolet radiation, thereby producingan anisotropic conductive film having a thickness of about 4 to about 40μm.

In another embodiment, the anisotropic conductive film composition mayinclude a binder part, a curing part, an initiator, and conductiveparticles, wherein the binder part includes at least one of an NBR resinand a urethane resin, and an anisotropic conductive film formed of thecomposition has an ion content of more than 0 ppm to about 100 ppm.

The binder part, the curing part, the initiator and the conductiveparticle are as described above. Further, the anisotropic conductivefilm composition may include a solvent. The solvent may be an organicsolvent, e.g., toluene, without being limited thereto.

In still another embodiment, an apparatus includes the anisotropicconductive film or an anisotropic conductive film formed of theanisotropic conductive film composition. The apparatus may includevarious types of display apparatuses, e.g., liquid crystal displays(LCD), and semiconductor devices which use anisotropic conductive filmsas a bonding material between modules.

Next, the embodiments will be described in more detail with reference tothe following examples. However, it should be understood that theembodiments are not limited to the illustrated examples and may beembodied in various different ways.

Embodiments that are not included herein will be readily recognized andappreciated by those skilled in the art, and an explanation thereof isomitted.

EXAMPLES Preparative Example 1 Preparation of NBR Resin Having IonContent of 10 ppm

100 g of an NBR resin (N-34, Nippon Zeon) was diluted in MeOH toeliminate ion impurities. The ion content of the NBR resin, measured byion chromatography using an automated combustion system, was decreasedfrom 600 ppm to 10 ppm.

Preparative Example 2 Preparation of Urethane Resin Having Ion Contentof 10 ppm

100 g of a urethane resin (NPC7007T, NANUX) was diluted with methylethyl ketone to eliminate ion impurities. The ion content of theurethane resin, measured by ion chromatography using an automatedcombustion system, was decreased from 400 ppm to 10 ppm.

Preparative Example 3 Preparation of Polyurethane Beads Having IonContent of 10 ppm

100 g of polyurethane beads (MM-101-MS) was diluted with methyl ethylketone to eliminate ion impurities. The ion content of the polyurethanebeads, measured by ion chromatography using an automated combustionsystem, was decreased from 500 ppm to 10 ppm.

Example 1 Preparation of Anisotropic Conductive Film Composition

As a binder part serving as a matrix for formation of a film, 24 wt % ofacrylic resin (alkyl methacrylate resin (Molecular weight Mw: 90,000g/mol, Acid value: 2 mgKOH/mg, MMA, BA, cyclohexyl methacrylatecopolymer)) and 40 wt % of the NBR resin having an ion content of 10 ppm(N-34, Nippon Zeon) prepared in Preparative Example 1 were used. As acuring part, 25 wt % of urethane acrylate (NPC7007, NANUX) and areactive monomer of radical polymerizable (meth)acrylate monomersincluding 1 wt % of 2-methacryloyloxyethyl phosphate, 2 wt % ofpentaerythritol tri(meth)acrylate and 2.5 wt % of 2-hydroxyethyl(meth)acrylate were used. 2.5 wt % of lauryl peroxide was used as aheat-curing initiator and 3 wt % of insulated conductive particles(Diameter: 3 μm, Sekisui) were used as a conductive filler. A filmcomposition was prepared using these components.

Examples 2 to 4 and 6 Preparation of Anisotropic Conductive FilmComposition

A film composition was prepared in the same manner as in Example 1except that the composition of the binder was changed as shown inTable 1. As a urethane resin, the urethane resin prepared in PreparativeExample 2 was used.

Example 5 Preparation of Anisotropic Conductive Film Composition

A film composition was prepared in the same manner as in Example 1except that the composition of the binder was changed as shown in Table1 and the polyurethane bead prepared in Preparative Example 3 was used.

Comparative Examples 1 and 2 Preparation of Anisotropic Conductive FilmComposition

A film composition was prepared in the same manner as in Example 1 or 2except that a non-ion exchanged NBR resin (Ion content: 600 ppm) or anon-ion exchanged urethane resin (Ion content: 400 ppm) was used.

TABLE 1 Comparative Example Example 1 2 3 4 5 6 1 2 Acrylic resin  24 24  24  24  24 —  24  24 NBR Ion  40  35 —  20  37  24 — — resinexchanged Non-ion — — — — — —  40 — exchanged Urethane Ion —  5  40 20 — 40 — — resin exchanged Non-ion — — — — — — —  40 exchanged Polyurethanebead — — — —  3 — — — (Ion exchanged) Curing part + heat-  36  36  36 36  36  36  36  36 curing initiator + conductive particle Total 100 100100 100 100 100 100 100

Experimental Example Evaluation of Physical Properties of AnisotropicConductive Films

100 g of each anisotropic film composition prepared in each of Examples1 to 6 and Comparative Examples 1 and 2 was dissolved in 20 g of tolueneand liquefied, and then was stirred at 25° C. for 1 hour. The productwas applied to a release film to a thickness of 16 μm and dried at 70°C. for 15 minutes to volatilize the toluene, thereby producing ananisotropic conductive film. The anisotropic conductive films wereevaluated in terms of ion content, electrical conductivity, initialappearance and connection reliability based on whether corrosion occursafter being left at 85° C. and RH 85% for 250 or 500 hours. Results areshown in Table 2.

<Methods of Evaluation of Physical Properties>

1. Ion content: Measured by ion chromatography using an automatedcombustion system.

2. Electrical conductivity: 0.4 g of each anisotropic conductive filmwas put in 20 g of purified water and boiled at 100° C. for 10 hours,after which a product liquid was put in a standard conductivitymeasurement cell having a diameter of 1 cm, followed by measurement ofelectrical conductivity at a compensation temperature of 25° C. using aconductivity meter (EcoMet C75, Istek)

3. Initial appearance: Each anisotropic conductive film was left at 25°C. for 1 hour. The anisotropic conductive film was connected bytemporary pressing at 70° C. for 1 second and by final pressing under4.5 MPa at 180° C. for 5 seconds using metal electrode glass (Mo/Al/Mostructure, Samsung Electronics) and a chip on film (COF, SamsungElectronics). 10 specimens of each anisotropic conductive film wereprepared and evaluated to identify whether an initial abnormality inconnection occurred.

4. Reliability: Each anisotropic conductive film was left at 85° C. andRH 85% for 250 or 500 hours, and the appearance was observed to identifywhether corrosion occurred.

TABLE 2 Comparative Example Example 1 2 3 4 5 6 1 2 Ion content N.D.N.D. N.D. N.D. N.D. N.D. 122 108 after forming film (ppm) Electrical26.7 27.2 29.6 28.7 27.8 28.1 266 154 conductivity (μS/cm) InitialNormal Normal Normal Normal Normal Normal Normal Normal appearanceReliability Normal Normal Normal Normal Normal Normal Corroded Normalafter 250 hours Reliability Normal Normal Normal Normal Normal NormalCorroded Corroded after 500 hours * N.D.: The automated combustionsystem performing ion chromatography cannot detect ion concentrations of30 ppm or less.

As can be seen from Table 2, the anisotropic conductive films accordingto Examples 1 to 6 do not have a high ion content and electricalconductivity and did not cause corrosion after 500 hours, exhibitinghigh connection reliability. However, the anisotropic conductive filmsincluding the NBR resin or urethane resin, which have an ion contentgreater than 100 ppm according to Comparative Examples 1 and 2, have ahigh ion content and electrical conductivity and exhibit unsatisfactoryconnection reliability.

By way of summation and review, with the recent trend toward light, slimand simple IT devices and flat panel displays having increasedresolution, the width of a device circuit becomes narrower. In aconventional circuit having a large width, corrosion occurring in partof a metal electrode in the circuit does not cause a short circuit ofthe entire circuit. However, in recent circuits having narrower pitches,when corrosion occurs due to a narrow metal electrode in an electrodecircuit, it may cause a short circuit, affecting connection reliability

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope as set forth in thefollowing claims.

What is claimed is:
 1. An anisotropic conductive film, comprising: abinder part; a curing part; an initiator; and conductive particles,wherein the binder part includes at least one of a nitrile butadienerubber (NBR) resin and a urethane resin, and the anisotropic conductivefilm produces an electrical conductivity of 1 μS/cm to about 100 μS/cmwhen 0.4 g of the anisotropic conductive film is put in 20 g of purifiedwater and boiled at 100° C. for 10 hours, after which a product liquidis put in a standard conductivity measurement cell having a diameter of1 cm, followed by measurement of electrical conductivity at acompensation temperature of 25° C. using a conductivity meter.
 2. Theanisotropic conductive film as claimed in claim 1, wherein theanisotropic conductive film has an ion content of more than 0 ppm toabout 100 ppm.
 3. The anisotropic conductive film as claimed in claim 1,wherein the anisotropic conductive film has an ion content of more than0 ppm to about 50 ppm.
 4. The anisotropic conductive film as claimed inclaim 1, wherein the binder part includes the NBR resin, and the NBRresin has an ion content of more than 0 ppm to about 100 ppm.
 5. Theanisotropic conductive film as claimed in claim 1, wherein the binderpart includes the urethane resin, and the urethane resin has an ioncontent of more than 0 ppm to about 100 ppm.
 6. The anisotropicconductive film as claimed in claim 1, wherein the binder part furtherincludes an acrylic resin.
 7. The anisotropic conductive film as claimedin claim 6, wherein the binder part includes about 20 to about 80% byweight (wt %) of the acrylic resin and about 20 to about 80 wt % of theNBR resin, the NBR resin having an ion content of more than 0 ppm toabout 100 ppm.
 8. The anisotropic conductive film as claimed in claim 6,wherein the binder part includes about 20 to about 80 wt % of theacrylic resin and about 20 to about 80 wt % of the urethane resin, theurethane resin having an ion content of more than 0 ppm to about 100ppm.
 9. The anisotropic conductive film as claimed in claim 6, whereinthe binder part includes about 20 to about 90 wt % of the acrylic resin,about 5 to about 55 wt % of the NBR resin, the NBR resin having an ioncontent of more than 0 ppm to about 100 ppm, and about 5 to about 40 wt% of the urethane resin, the urethane resin having an ion content ofmore than 0 ppm to about 100 ppm.
 10. The anisotropic conductive film asclaimed in claim 1, wherein the binder part further includes at leastone thermoplastic resin selected from acrylonitrile, polyamide, olefinand silicone resins.
 11. The anisotropic conductive film as claimed inclaim 1, wherein the curing part includes at least one of a urethane(meth)acrylate and a (meth)acrylate monomer.
 12. The anisotropicconductive film as claimed in claim 1, wherein the initiator includes aradical initiator.
 13. The anisotropic conductive film as claimed inclaim 1, wherein the anisotropic conductive film includes about 20 toabout 78 wt % of the binder part, about 20 to about 50 wt % of thecuring part, about 1 to about 10 wt % of the radical initiator and about1 to about 20 wt % of the conductive particles in a solid state.
 14. Theanisotropic conductive film as claimed in claim 1, wherein theanisotropic conductive film further includes a polyurethane bead. 15.The anisotropic conductive film as claimed in claim 14, wherein thepolyurethane bead includes an ion-exchanged polyurethane bead.
 16. Theanisotropic conductive film as claimed in claim 14, wherein thepolyurethane bead has an ion content of more than 0 ppm to about 10 ppm.17. The anisotropic conductive film as claimed in claim 14, wherein thepolyurethane bead is included in an amount of about 1 to about 10 partsby weight based on 100 parts by weight of the anisotropic conductivefilm in terms of solid content.
 18. An apparatus comprising theanisotropic conductive film as claimed in claim
 1. 19. A composition foran anisotropic conductive film, the composition comprising: a binderpart; a curing part; an initiator; and conductive particles, wherein thebinder part includes at least one of an ion exchange treated nitrilebutadiene rubber (NBR) resin and an ion exchange treated urethane resin,and the anisotropic conductive film produces an electrical conductivityof 1 μS/cm to about 100 μS/cm when 0.4 g of the anisotropic conductivefilm is put in 20 g of purified water and boiled at 100° C. for 10hours, after which a product liquid is put in a standard conductivitymeasurement cell having a diameter of 1 cm, followed by measurement ofelectrical conductivity at a compensation temperature of 25° C. using aconductivity meter.